Field of the Invention
This invention relates to switchgear and more particularly to a bolted joint connection between terminals of a circuit breaker and the bus conductors to which the circuit breaker is connected.
2. DESCRIPTION OF THE PRIOR ART
Circuit breakers having larger ratings such as the drawout type breaker or metal-enclosed switchgear, are provided with multiple connectors on each pole to multiply the number of contacting areas in order to minimize electrical resistance and the resulting heat generated thereby. In the past, various means have been provided for minimizing the electrical resistance developed at the joint between the pole terminals and the load and line bus conductors, including bolted joints and the like. A disadvantage with the particular type of bolted joints used heretofore has been the relative inaccessibility of the bolted connections when a particular circuit breaker is installed or withdrawn from service. Most prior bolted connections have necessitated not only access to the terminal or rear side of the circuit breaker, but also a requirement for turning off the power for safety reasons.
Associated with the foregoing has been a problem of inserting multi-pole circuit breakers into operating position. Circuit breakers having two or more poles are not always readily inserted into position, because each pole includes incoming and outgoing terminal fingers with a plurality of interfitting bus conductor fingers. A tight fit between the fingers of the bus conductors and terminals is necessary for satisfactory electrical conductivity. On the other hand, the greater the number of interfitting conductor fingers and terminal fingers, the greater the effort necessary to install the circuit breaker in place. Manifestly, where only two interfitting bus conductor fingers are involved for a single joint, the amount of effort required for assembling the conductors is minimal, such as for conductors of a bus duct as disclosed in U.S. Pat. No. 3,408,454, issued Oct. 29, 1968, to S. S. Fouse.